Pedal travel simulators make a pedal travel (a lever travel in the case of a parking brake) possible in power-operated hydraulic vehicle braking systems upon an actuation of a master brake cylinder. With power operation, the master brake cylinder serves as a setpoint generator for a hydraulic braking pressure, which is not generated by the master brake cylinder, but by external energy, for example using a hydraulic pump. In the case of power braking, the master brake cylinder is hydraulically disconnected from the vehicle braking system, for example by the closing of a valve, and upon its actuation displaces brake fluid into the pedal travel simulator.
A pedal travel simulator usually includes a cylinder and a piston displaceable in the cylinder, as well as a piston spring, which acts on the piston counter to a pressure application from the master brake cylinder. With a power operation of a vehicle braking system, the pedal travel simulator is hydraulically connected to a master brake cylinder, which upon its actuation displaces brake fluid into the cylinder of the pedal travel simulator, whereby the piston is displaced counter to a spring force of the piston spring in the cylinder of the pedal travel simulator.